1. Field of the Invention
This invention relates to alpine ski boots having a rigid shell base topped by an upper that is at least partially journalled on the shell base, and more particularly, to apparatus affecting the interior-posterior flexion of the upper.
2. Description of Background and Relevant Information
Conventional alpine ski boots having a rigid shell base include an upper that is forwardly inclined with respect to the vertical at a given angle generally called the "advance angle", the value of which is in the range of approximately 13-20.degree.. The optimum advance angle depends upon the conditions of use of the boots, such as competition, the nature of the terrain, quality of snow, etc, and upon the morphology of the skier. For this reason, it is desirable to be able to vary the advance angle at will. Numerous solutions have been developed; and as a result, most of the alpine ski boots in current use include expedients for adjusting the advance angle.
European Patent Office Publication Nos. 205,127 and 071,055, as well as French Patent No. 2,276,850, each discloses apparatus for modifying the angular position of the front element of an upper of a rear entry ski boot, and consequently, the tibial support afforded by the boot to the lower leg of the skier. In such apparatus, however, modification of the advance angle requires a corresponding adjustment of the closure means by which the upper of the boot is held on the lower leg of the skier. That is to say, the approach position of the rear element, or rear spoiler, of the upper of the boot, must be adjusted with respect to the front element or cuff of the boot each time the advance angle is adjusted.
Other boots, such as those described in Italian Patent No. 194,289 and European Patent Office Publication No. 133,237, utilize apparatus that permit modification of the angular position of the cuff with respect to the shell base followed by modification of the rear spoiler. Such apparatus do not modify the conditions of closure of the upper on the lower leg as previously described, but vary the amplitude of flexion by reason of the change of the relative position of the cuff with respect to the shell base in a manner inversely proportional to the value of the advance angle, i.e., maximum advance-minimum amplitude and vice versa.
It is an object of the present invention to provide an alpine ski boot whose adjustment apparatus for the advance of the upper with respect to the shell base achieves a constant amplitude of flexional movement for each of the angular positions of the upper on the shell base.